Alpha- and beta-Adrenergic receptors and prostaglandin receptors are being studied in human blood cell preparations. The ability of adrenergic drugs to activate or inhibit adenylyl cyclase is used as a measure of their function. Binding of tritiated adrenergic receptor antagonists to membrane receptors on blood cells is being measured. These correlative measures are being used to assess Alpha and beta-adrenergic physiological function in normal human beings, patients with various psychiatric disorders, and patients receiving different psychopharmacologic agents.